Question

R programming

1. Write an assignment statement to complete each of the following without using diff() and sign(): (a) generate a vector of the difference between the ith element and the (i+1)th element in a vector v of integers, where i = 1: length(v), and (b) generate a vector of the sign of each elements in the vector generated in (a) as follows: ‘p’ for positive, ‘n’ for negative. (Use v ⟵ c(1,4,7,2,1) for testing.)

2. Write a function that assigns an integer value, say 7, to an integer n and generate a symmetric metrics where the diagonal elements are all zeros, and the elements following the 0 value are consecutive odd numbers. For example, the first row of a 5X5 matrix contains “0, 1, 3, 5, 7”; the second row contains “1, 0, 3, 5, 7”. You may use any function that we have used in our lectures to write your function. (You cannot hard-code the matrix; it needs to be generated.)

Answer 1

1.

SOURCE CODE:

v=c(1,4,7,2,1)
ans=c()
for(i in 1:length(v)){
if(i+1<=length(v))
ans=c(ans,(v[i]-v[i+1]))
}
print(ans)
ans2=c()
for(i in 1:length(ans)){
if(ans[i]<0)
ans2=c(ans2,'n')
else
ans2=c(ans2,'p')
}
print(ans2)

SCREENSHOTS:

2.

SOURCE CODE:

library(R.utils)
n=7
tup=c()
i=1
while(i!=n+2)
{
tup=c(tup,i)
i=i+2
}
len=length(tup)+1
m=matrix(,nrow=0,ncol=len)
for (i in 1:len)
{
temp=insert(tup,at=i,values=0)
m=rbind(m,temp)
}
print(m)

SCREENSHOTS: